Control system



July l, 1930. J. A. CLARKE, JR 1,768,745

` CONTROL SYSTEM Filed Nov. 30. 1927 3 Shets-Sheet l who @sa im 26%-@rou/1d Squence of ..5`w/7'c/7es Comb/baffo /Vo/ches WITNESSES: INVENTORJuly l, 1930. J. A. CLARKE. JR 1,768,745 f CONTROL sYsTBl Filed Nav. so,1927 s sheets-sneu 2 WMJ'M/ M2M I July l, '1930-4 l J. NCLARKE, JR1,768,745

' common sys'rsl Filed Novf'so. 1927 I 3.suxsnot"z '50 7 'g s ap I zsfsof 2v" zaf JMG@ W- INvl-:Nfon

Patented July 1, 1930 g UNITED STATES PATENT OFFICE JOHN A. CLARKE, JB.,0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC &MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA CONTROL SYSTEMApplication led November 30, 1927. Serialk No. 236,810.

My invention relates to` s stems of control for dynamo-electric mac inesand more particularly to the control of electric railway motors.

The object of my invention, generally stated, is the provision of acontrol system that shall be simple and efficient in operation andeconomically manufactured and installed.

A more specific object of the invention is to provide for the use of camswitches that are protected by unit switches or contactors to jointlyset up the proper circuits to effect the operation of a plurality ofmotors in different arrangements and the transition from one arrangementto another during progressive movement of a controller in one direction.

A further object of the invention is to provide for the setting up ofthe proper circuits to suitably effect the operation of a plurality ofymotors in series and in parallel relation and'through a closed-circuittransi` tion from the one to the other.

Another object of the invention is to provide for effecting theacceleration of the motors during the parallel relation thereof by thecutting out of the resistance units in the sequence used duringy theseries operation of the motors.

Other objects of the invention will, in part, be obvious and in partappear hereinafter.

The invention, accordingly, is disclosed in the embodiment thereofyshown in the accompanying drawing and comprises the combination ofelements and arran ement of parts which will be explained in t e systemhereinafter set forth, and the scope of which will be indicated in theclaims.

For a fuller understanding of the nature and objects of the invention,reference may be had to the following detailedfdescription taken inconnection with'the accompanying drawing, in which:

Figure 1 is a diagrammatic view of the main circuits of a control systemconnected inl accordance with this invention; l f

Fig. 2 is a sequence chart of well-known form for indicating thepreferred order of operation of the Various 'switches that areillustrated in Figs. 1, 3 and 4;

Fig. 3 is a diagrammatic view of the auxiliary or control circuits,which are connected 'and arranged in accordance with the features ofthis invention; and

Fig. 4 is a diagrammatic view of certain auxiliary circuits provided topermit multiple-'unit operation.

Figs. 5 to 11 inclusive, show dia rammatically the circuit connectionsestab ished during the transition from series to parallelmotor-circuitconnections; and

` Fig. 12 is a diagrammatic view of the main circuit connections as theystand when the controller is actuated to position 15 to establishparallel motor circuit connections; and

Fig. 13 is a diagrammatic view of the motor circuitconnectionsestablished after a predetermined number of motors have beenisolated.

Although the circuits shown in Figs. 1 and 3 are both necessary toeffect the complete operation of the control system, the features of thesystem may be more clearly set forth by describing the circuitsseparately. Consequently, the main circuit connections will first bedescribed generally, in conjunction with the sequence chart and theillustrated auxiliary circuit connections will be set forthvlater.

-Referringnow to Figure 1, the system illustrated comprises suitablesupply-circuit conducto-rs, such as trolley 25 and ground 26. As shown,four dynamo-electric machines 27 and 30, inclusive, of the commutatortype, are connected in series groups of two each, in the circuit. Itwill be readily understood that, while only Vfour motors are shown inthis particular diagram, any other number might be used and connected inpairs or otherwise.

The supply of current to the motors is controlled by a plurality of lineswitches 31 to33, inclusive, and the ymain motor circuits are controlledby n a plurality ofV lmotor switches 34 to 39, inclusive. Asillustrated, a number of resistance units 40 to 50, inelusive, areprovided for controlling the acceleration ot the motors when connectedin the various arrangements, such as series and parallel.

The resistance units may be cut into and out of the motor circuits bymeans of switches 5l to 60, inclusive. These resistor switches are ofthe unit type and adapted for the making and breaking of circuits inwhich large currents are flowing.

In order to establish the desired grouping of the motors and the propercircuit arrangements, cam switches 61 to 73, inclusive, are pr vided andare operated, when the motors are cle-energized, by means of acontroller 74 and the auxiliary circuits shown in Fig. to set up anypredetermined motor circuits to permit series and parallel operation ofthe motors. After the proper circuits have been set up, the main motorcircuits are closed or broken by means of the motor switches 34, 35, 37and 39, inclusive, which are of the unit type and adapted for breakingcircuits carrying heavy currents.

Referring now to the sequence chart, Fig. 2, it will be noted that whenthe controller stands in its off position, the cam switches 6l and 64,which are operated in a manner to be hereinafter described, are closed.Further, ono of the two groups of cam switches 66 to 6i), inclusive, or7 O to 7 3, inclusive, is also closed, these switches being controlledby the setting of `the reversing drum 100, which is provided forchanging the flow of current in thc motor field windings. Assume that itis desired to operate the motors in what for convenience will bedesignated the forward direction; then, upon setting the reversing drinn100 in its forward position, cam switches 66 to 69, inclusive, areclosed.

lVhen the controller 74 is advanced one notch, the line switches 3l to33, inclusive, the motor switches 35 and 3S, and resistor switch 36 areclosed. Current now flows from the trolley 25 through the line switches3l to 323, inclusive, resistance units 46 to 50, and 45, inclusive,resistor switch 36, resistance units 40 to 44, inclusive, motor switch35, the armatures 27a and 28a of motors 27 and 2S, respectively, camswitch 6l, motor switch 3S, the armatures 29a and 30a of the motors :29aud 30, respectively, cam switch G8, motor field windings 29]c and BOf,cam switch 6), motor cutout switch 76, cam switches 64 and 66, motorfield windings 27,1" and 23,2", cam switch 67, and motor cutout switch75 to ground at Q6. The motors are now connected in series relation andare set in operation. As the controller 74 is advanced step-by-step, theresistance units 40 to 50, inclusive, are cut out in the desiredsequence, as indicated in the sequence chart Fig. 2. Then the last notchof the series operation is reached, the motor switches 34 and 37 areclosed.

The continuance of the progressive notching of the controller 74eil'ects transition from the series connections ofv the motors toparallel connections. '.l`he transition is accomplished without openingall the motor circuits in a manner that will be hereinafter set forth.

As the controller 74 advances step-by-step, the cam switches 62 and 63are closed, then the motor switch 3S is opened aud the cam Switchclosed. When the controller reaches the last point of the transition,the motor switch 39 is closed. It will be evident that the opening ofthe motor switch 38 prior to the closing of the motor switch 39 willprevent all possibility of establishing a short circuit through themotor switches 39 and 38 to ground.

The motors are now connected in two series groups and the groups inparallel. Motors 27 and QS are included in one series group, with motors25) and 8O in another.

The circuit for motors 9.7 and 28 includes the trolley 25, line switches31 to 2li-, inclusive, motor switch 34, resistance units fl() to 44,inclusive, motor switch 35, motors Q7 and Q8, cam switches 62, 63 and66, field windings 27] and 28j', cam switch G7 and switch to ground. Itwill also be observed that the circuit for the motors Q9 and 30 includesthe trolley 25, line switches 31 to 33, inclusive, resistance units 46to 50, inclusive, motor switches 37 and 39, the armatures of the motors29 and 30, cam switch 68, field windings 29] and lOf, cam switch 69,switch 7G and cam switch G5 to Ground.

As the controller continues its Forward movement, the resistance unitsare cut out in a predetermined sequence, as indicated in Fig. 2. It willbe noted that when the motors are connected in arallel relation, theresistance units are divided into two groups 40 to 44, inclusive, and 46to 50, inclusive. In order to maintain proper halance in the circuits, aresistance unit is first cut out of one group, and then another out ofthe other group, such, for example. ai: when resista-nce unit 44 is cutout oi the tirst group, then resistance unit 5() is cut out of the othergroup ou the next step of thc controller.

Referring now to Fig. 3, it will be observed that the controller 74comprises two Contact segments 74a and 74?) so shaped as to suitablyco-operate with a plurality of Contact fingers 77 to 96, inclusive, toset up certain motor circuits in the desired :Z-equence. The circuitsthat are established and broken by the different parts of contactsegments 74a and 741; will be specified from time to time as thedescription proceeds.

As shown, the Contact fingers '77 to 9S, inclusive, are connected toconductors that are desi nated by corresponding numerals and to t evarious switch coils and contact Loo members, as will be hereinafter setforth. The contact fingers and the corresponding conductors leadingtherefrom are designated by the same numerals in order to simplify thedetailed description of the control system. i

The electrical energy necessary for the operation of the variousswitches and control drums may be obtained from any suitable sourcethrough the main conductor 99. The source of supply may be a storagebattery or a motorenerator set.

A reversing rum of a well-known type is provided for controlling thearrangement of predetermined circuits, whereby the ow of current in themotor-field windings may be reversed in order to rotate themotors eitherin a forward or a reverse direction. As isy usual practice, thereversing drum is interlocked with the controller. Further, when thereversing drum 100 is set in its forward position, an interlock drum101, which is disposed for operation simultaneously with the motorfield-winding reverser 100, is also set yin its forward position throughthe energization of a coil 102. A coil 103 may be energized by throwingthe reversing drum 100 into its reverse position to effect the ,settingof the interlock drum 101 ofthe motor field-winding reverser 100 forreverse operation of the motors 27 to 30, inclusive. These coils 102 and103 preferably control the actuation ofthe magnet valves of a. separateair engine provided for rotating the interlockl drum 101.

The reversing drum 100 includes a plurality of contact segments 104 to111, inclusive. The contact segments 104 to 107, inc1usive,care disposedfor engaging Contact fingers 112, while the contact segments 108 to 111,inclusive, are arranged for engaging contact fingers 113. f

f As will be observed, a control andcircuit breaker resetting switch 114is interposed between the source of current 'supply and the reversingdrum 100. A conductor 115 is provided for connecting kthe control switch114 to a-contact finger that is located between the contact segments104and 105 of the reversing drum.

Assuming that it is desired to move the locomotive in the forwarddirection, the reversing drum 100 is thrown into its forward position F,thereby operating contact segment to establish connection between theconductors 115 and 81. At the same time, the contact segment 110 engagestwo of the contact fingers 113 and establishes a circuit from thecontrol switch 114 through conductor v97, .which is connected to thecontact finger 98 of the controller 74 by means of ya contact platel117, which is disposed to bridge the contact fingers 97 and 98 when thecontroller is in its off position.'

When the control switch 114 is thrown to the right, as viewed in Fig. 3,the conductor 116 is energized. In this manner, a circuit is completedthrough the parallel-connected actuating coils 1l8a, 1185, and 1180 of aplurality of series-related circuit-breakers 118 and a conductor 148 toground at 131, whereby the circuit-breakers are closed.

After the reversing switch 100 has been operated and the control switch114 is thrown to the left, the conductor is energized. The controller 74may now be operated step-by-step to effect the setting up of thenecessary motor circuits for the series operation of the motors. As willbe seen, when the controller is moved to notch 1, the contact segment74a bridges the cony tact fingers 77 and 78 while the contact seg vment741) bridges the contact fingers 80, 8l,

82 and 87.

In this manner, a circuit is set up from the source of power supply,through the conductor 99, control switch 114, conductor 115, contactsegment 105, conductor and contact finger 81, contact segment 74h,conductor 82, contact segment 106, conductor 120, contact segment 119provided on the drum 101, and conductor 78 to contact segment 74a,thereby energizing the latter.

When the contact segment 74a is energized, current flowsthroughconductor 77 and the coil 121 of a magnet valve that is provided` forcontrolling the operation of preferably an air engine of a well-knowntype, which is dis osed to rotate an interlock drum 122. s ywill beobserved, this drum is provided with a plurality of contact members 123to 128, inclusive, that are disposed to set up predetermined controlcircuits, and is further provided with suitable cam members foractuating certain cam switches, thereby establishing the proper motorcircuits for series and parallel operation. l

In this particular control system, the energization of the coil 121effects the operation of the air engine to set the drum 122 in what isvkdesignated by the letter S as its series position. Thus, when thecontroller 74 is advanced to the'first notch, the drum 122 isimmediately rotated to its position S. f

There is also a position designated P to which the drum may be moved toeffect the establishment of themotor circuits required for paralleloperation of the motors.

As indicated by dotted lines, there are a number of intermediatepositions through which the drum passes as it rotates from` P to S orvice versa.

Further, the cam switches 61 and G4 are disposed to be closed by-thecams operated with the drum 122 as it rotates toward its S position andthey are rretained closed as long as the drum remains set inl its seriesposition. 'The cam switches 66 to 69, in-

elusive, were closed when the coil 102 was| energized upon the settingof thc reversing drum 100. Consequently, the. proper motor circuits areestablil'iet. Yfor the s' fies operation of the niotors, and upon theclosure oi" the protecting line and motor switches, the current flows aspreviously traced.

Another circui up when the coi irollcr 74 is moved to its i is 'from theenergized .ct segment .n rhrengh contact finger and conductor 37, theactuating coil of the switch 35 and cnt-ont wirh 13V` to ground at 131,whereby the ci: fure ot' the motor switch 35 is effected.

As shown, an Vint irlocl 35i-in is provided on the switch and servesy toestablish a connection between act ting coil of switch 3S, and a cut-outswitch 132 that is connected to ground at 131. Since the drum 122 is inseries position, the actuating coil of the switch 33 is connected to theconductor 37 and energized when the switch 35 is closed, thereby closingthe switch 38.

the

In order to effect the el ire of the line switches 31 to 33, inclusiUeiloc;

3S in, operated by the sw l i vided and disposed. to cstabl a connectionbetween the energized cer ctoil 7 8 and a contact finger 134, which 1spositioned to engage contact plate 127 when the drum 122 is in itsseries pos tV i Another contact finger 134, which is disp l to engageplate 127 when the drum. is in series position, is connected to theactuating coils of the switches 31 to 33, inclusive.

Current now flows from the energized conductor 7S, through interlock3S-in, two of the contact fingers 134 that are bridged by the contactplate 127, the coils of the switches 31 to 33, inclusive, two of thecontact fingers 134 that are bridged by the contact plate 128, two ofthe contact terminals 136 that are bridged by the interlock -out whenthe switch 60 out, and the circuit-breakers 113 to ground at 131. Inthis manner, the line switches 31, 32 and 33 are closed.

Another circuit set up when the controller is advanced to notch 1extends from the energized contact segment 745, through conductor 80,and the actuating coil of the switch 3G to ground, to effect the closureof switch 36. Therefore, on the actuation of the controller 74 to thefirst position,` the line switches 31 to 33, inclusive, and the motorswitches 35 and 39 resistor switch 3G are closed. Since the series motorcircuits were partially established when the drum 122 was rotated to itsS position, the closure of the line and motor switches sets the motorsin operation.

As will be observed, the contact segment 74?) is stepped so that theconductors will be energized in the following order, 88, 89, 83, 90 to96, inclusive. Consequently, the

pro-

operating coils of the switches 51 to 60, inclusive, are energized tocut out the various resistance units in a predetermined order. In thismanner, the motors, while connected in series arrangement, may beaccelerated step-by-step.

When the controller is moved to position 12, as indicated in Fig. 3, thecontact fingers 84 and 85 are engaged by the contact segment 7 4b andthe corresponding conductors are energized. Current now flows throughthe actuating coils of the switches 34 to 37, inclusive, and effects theclosure of the latter.

Assume now that it is desired to set up the proper circuits for paralleloperation of the motors 27 to 30, inclusive. In order to effecttransition from series to parallel, the progressive movement of thecontroller 74 is continued. For convenience in description, the movementof the controller through transition will be divided into six steps. Aswill be noted by reference to the sequence chart, Fig. 2, these stepsare designated A to F, inclusive.

As shown, the contact segment 746 is out away so that when thecontroller reaches position A of the transition, the contact fingers 91to 96, inclusive, 83 and 84 are disengaged, thereby effecting thede-energization of the corresponding conductors. Consequently, theswitches 51 to 54, inclusive, and 56 to 59, inclusive, are opened,introducing the resistance units 41 to 44, inclusive, and 46 to 47,inclusive, into the motor circuit. At the same time, the contact finger8() is released from the Contact segment 746, thus de-energizing the.corresponding conductor and opening the switch 36.

The contact segment 74a is cut away so that the Contact finger 77 andthe corresponding conductor are de-energized, thereby cutting off thesupply of current to the actuating coil 121 of the magnet valve forcontrolling the drum 122.

It will be observed that a depending portion is provided on the contactsegment 74a of the controller that engages contact finger 79, energizingthe corresponding conductor. Current then flows through conductor 79,the contact fingers 134 thatare bridged by the contact plate 125, anactuating coil 137 of an inverted magnet valve which controls theoperation of the air engine of the type shown in Patent 1,229,543 thatis provided for rotating the drum 122. The energization of the coil 137effects the opening of a magnet valve causing the air engine to rotatethe drum 122 from its series position to its parallel position P.

Considering now step B of the transition, the cam switches 62 and 63 areclosed as the drum 122 rotates to its P position. As will be observed byreference to Fig. 1, the

i :in

, ing coil of the switch 38.

closure `of switchesk 62 and 63 tem orarily short-circuits motors 29 and30. urther, the rotation ofthe drum 122 to its lP posi,`

tion effects the release of the contact gers 134 that are bridged by thecontact to 33, inclusive, may be supplied through a holding circuitcomprising interlock 31-in,

which establishes connection between the i conductor 78 and theoperating coils of the line switches Since a circuit from the energizedconductor 78 to the actuating coils of these switches isestablishedthrough the interlock 31-in, the circuit through the late 127may be opened without opening the line switches.

Asythe drum 122 continues to rotate after the release of the contactfingers from plate 127, the contact fingers that are brid d by thecontact plate 123 are released, t ereby effecting the de-energization ofthe actuat- The opening of the switch 38 is accomplished before theclosing of the switch 39, preventing all possibility of establishing ashort-circuit through the switches 38 and`39 to ground. Further, whenthe switch 38 is opened, the interlock 38-in is o cned.

When the control er 74 reaches positionk C during thetransition, thecontact finger 86 is engagedk bythe contact segment 741), therebyenergizing the conductor 86 and closing the switch 54. The purpose ofclosin'gthe switch 54 will appear hereinafter. Cn the next step D of thetransition, the cam switches 61 and 64 are opened, effecting theseparation of the two groups oi?y motors. Since the motors 29 and 30 areshort-circuited, the switches ma be opened without breaking any energizemotor cir cuits.

`The contact lingers 134, bridged by the contact plate 125, are nowreleased. Since the switch- 38 is open and an interlock 38-out connectsthe conductor 79 to the coil 137, the breaking of the circuit throughthe plate 125 does'not effect the de-energization of the coil 137k or aninterruption in the rotation of the drum 122.

Considering now step E of ythe transition, the drum 122 is rotated farenough to close the cam switch 65. Finally,-when the drum 122 reachesits parallel position, the contact fingers 134 that are 'connected tothe operat' ingr coils of the switches 35 and 39, respectively, arcbridged by the contact plate 124. Current then flows from energizedconductor 87, through the contact fingers 134 that are bridged by thecontact plate 124, the actuating coils of the switches 35 and 39 andswitch 132 to ground at 131. *y y As will be observed, the contact plate128 when switch 31 is closed.y

56 to 59, inclusive.

isi of sufficient sizetomaintain continuously, lduring the rotation ofthe drum 122 from its series .to its parallel position,l the operatingcircuit of the switches 31 to 33, inclusive. Duringthe rotation of thedrum, it picks up one of the contact iingers 134 before it dropsanother, thereby assuring the continuance of thc switch-actuatingcircuits.

It will be noted that the interlocks (SO-in and (iO-out, operated withthe switch 60,

are provided for connecting the actuating coils of, thev switches 31 to33, inclusive, directly to ground at 131,.when the switch is closed andthrough the circuit breakers 118 lwhen the switch 1s out.

lAs will be readily understood .from an examination of the diagram shownin Fig. 3'on the final step F of the transition, the closing of switch39 connects the motors for operation in parallel relation. As theprogressive operation of the controller' is continued, a steppedportionprovided on the ycontact segment 74() effects the energization ofthe conductors 91 to'96, inclusive, in sequence, thereby energizing theactuating coils of the switches 51 to 53, inclusive, and Thus, theresistor switches are closed in order and a step-bystep accelerationofthe motors, while connected in parallel relation, is effected.

This process of changing from series to lparallel-motor-circuitconnections is generally termed a closed-circuit transition, since theLmotors 27 and 28 are continuously connected to the power source ywhilethe motors 29 and 30 are shunted.

Assumin that it is desired to change from paral el toseries-motor-circuit connections, then the controller .is actuated.toward its off position. The drum 122 vstands in its parallel positionand can not be actuated to its series position until the magnet 121 isenergized. It willbe observed that aninterlock 3l-out carried by theline switch 31 controls the actuating cir-k cuit of the magnet 121.Therefore, the magnet 121-can not be energized until the line switch 31is opened. The opening of the line switch can not be affected until thecontroller yreaches its olfk position. The closure of the switch 38, forconnecting the motors in series-circuit relation, depends on theposition ofL the drum 122. When the drum is in its series position, anactuating circuit for the vswitch 38 is estab-` lished through thecontact se ment 123 which bridges avpair of contacty ngers 134.Therefore, the actuating circuit for the switch 38 can not beestablished as long as the drum stands in its parallel position.

Therefore, the switch 38 can not be closed to establish series-circuitconnections for the motoruntil after the controller is actuated to itsolf position, opening the line switc 31. l

lVhen the controller reaches position 21, an extension et' the contactsegment 74b engages the contact finger 80, thereby effectingenergization of the conductor 80. Current now fiows through theactuating coil ot the switch 36 to ground at 131. The closure of switch36 establishes a circuit from the main source of supply through lineswitches 31 to inclusive, switch 34, and switches 3G, 55, 37, and 35, tothe motors.

Assume that for some reason, such as the short-circuiting of thewindings of one of the motors 27 or 28, it becomes necessary to cut outthis pair oi motors. Under such conditions, since the motors 29 and 30are connected in series, it is desirable to retain the connections estalished for the parallel operation of the motors and to effect theiracceleration by the use of the same number it resistance units that wasprovided for use during the series operation of the motors.

In order to provide tor the complete isoation ot one pair ot the motors,a plurality of cut-out switches and 76 with control cut-eut sv-fitches1130 and 132 are provided. Further, as shown, two cut-out interlocks 140and 141, which are closed when the control eut-ont switches 13() and 132are inserted in the conductor 7 7. 1t will also be observed that twomore interlocks, 144 and 145, which arc closed upon the opening of thecut-out interlocks 140 and 141, respectively, are provided forinterrupting a conductor extending between conductors 77 and 79. Theinterlocks 144 and 145 are arranged in parallel relation, so that bytheir independent operation the circuit between the conductors may beclosed. An interlock til-out, which is disposed to break the conductor77 when the'line switch 31 is closed, serves to establish the circuitthrough the cut-out interlocks 140 and 141 when the line switch is outand all the motors are connected in the circuit.

Since it is desirable to eifect the closure oi the interlock 54-in whenthe contact plate 14S is in its parallel position, two more interlocks,arranged in parallel relation, are connected between conductors 83 and86 and disposed tor actuation to their closed positions to completecircuits when the eut-out switches 130 and 132, respectively, areopened. It vill be noted that the cut-out plate 14S, when set in itsseries position. establishes a connection between the conductors 83 and86.

As set forth above, interlocks .140, 144 and 146 are associated with thecut-out switch 132. In practice, a variety of constructions may beprovided for effecting the actuation of the differentinterlocks, asdescribed, when the cut-out switches 130 and 132 are actuated.

A suitable construction may be made by providing springs, two of whichtend to retain continuousl the interlocks 14() and 141 in their closedYpositions while the others continuously tend to hold the interlocks 145to 147 open. It will be readily under stood that means may be associatedwith the cut-outl switches 130 and 132 or with harriers mounted overthem to compress the springs of the interlocks 140 and 141 and to extendthe actuating springs of the interlock 145 to 147, inclusive, as thecut-out switches are opened, Therefore, the interlocks may be actuatedby the operation of the cnt-ont switches.

In order to isolate, say for example, the motors 27 and 28, the cut-outswitch 13() is operated. This permits the spring-actuated interlock 140to open and the interlocks 144 and 146 to close. In this manner, thecircuit through the actuating coil 121 of the magnet valve isinterrupted and the coil (le-energized. Further, upon the closure of theinterlock 144, connection through conductor 142 is established betweenthe conductor 77 and the conductor 79. It will also be noted that theclosure of the interlock 146 establishes a connection between theconductor 83 and the conductor 86. The switch 75, which is generallymanually operated, is opened when the switch 130 is opened.

Assume that the controller 74 is in its olf position and the reversingdrum in its neutral position when the eut-out switch is opened. Then, inorder to set the motors in operation, the reversing drum 100 is moved toits forward position and the controller advanced to notch 1. The contactsegments 74a and 745 are then connected to the supply conductor 92) andthe conductors 77, 8() and 87 are energized.

The interlock 144 is in a circuit which is established from conductor 77through iuterl ck switch 144, conductor 142, conductor 79, interlock3Sout, actuating coil 137 of the inverted magnet valve that controls thellow of fluid pressure to the air-engine, contact plate 128, contactplate 135 and circuitbreakers 118 to the ground 131. Consequently, theair engine is set in operation and it rotates the drum 122 from itsseries position to its parallel position. The rotation of the drumeffects the opening of the cam switches 61 and 64.

1V hen the reversing drum is set, the drum 101 is also rotated to itsforward position. The simultaneous operation of the reversing drum andthe drum 101 may be accomplished in any suitable manner, such, forexample, as by the use of a mechanical connection.

Since the drum 101 is set in its forward position, the cam switches 66to 69, inclusive, are closed.

It will be observed that when the drum Ult! y motors. f e

Another circuit is established from th energized conductor 79, which isnow connected to conductor 44 throu h the interlock 139, the contactfingers 134 t at are bridged by contact plate 126, the actuating coilsof the line switches 31 to 33, inclusive, the contact fingers 134 thatare bridged by the contact plate 128, an interlock 149, which isassociated with the switch 59 yand is disposed to complete the circuitthrough the contact plate r135 when the line switch 59 is out, and thecircuit-breakers 118 to the ground 131. Therefore, the line switches 31to `33, inclusive, are closed. Consequently, the main motor circuit isclosed and current flows from the trolley through line switches 31, 32,and 33, the resistance units 46 to 50, inclusive, resistance unit 45,line switches 36, resistance units 40 to 44, inclusive, the motor switch39, motors 29'and 30 connected in series-circuit relation, cam switch68, field windings 29a and 30a, cam switch 69, switch 76 and camy switch65 to ground' at 26.

It is pointed out that the interlock 54i-n serves to assure thecompletion of the circuit through the line-switch actuating coils incase the drum 122a, which rotates with the drum 122, does not actvquickly. The interlock 54--in further insures the maintenance of thecircuit for energizing the coil .137.

Therefore, when the motors 27 and 28 are isolated, the same motorcircuit will ber established for motors 29 and 30 connected in seriesthat is established when the two motor groups are connected in parallelcircuit relation, with the exception that the resistors 40 to 50,inclusive, are connected in seriescircuit relation. Thea'cceleration ofthe motors isv effectedv b a progressive movement ofthe Acontroller 4 tocut out the yresistance units 40 to 50, inclusive, in the same sequenceas when the motors 27 to 30, inclusive, are connected in seriesrelation.

Assume that a short-circuit occurs in motor 27 when the motorv groups27--28 and 29-30 are connected in parallel relation. Underk suchconditions the circuit-breakers 118 will open. Then,-in order to isolatemotors 27 and 28, the' switch l130 is opened, permitting the actuationof the corresponding interlocks.

It will be readily understood from the preceding description, that theparallel drum 122 will be retained in its parallel position andtheswitch 39 closed. Then, upon thc movement of' the controller to itsoff position to venergize the coils 118@ to 1180, inclusive, to closethe circuit-breakers 118, the resistance units will be connected as forseries operation of the motors. Consequently, as the controller isadvanced, the motors 29 and 30 will be accelerated as in seriesoperation.

In order to adapt the control system for multiple unit operation, all ofthe conductors 77 to 97, inclusive, except 81 and 82, are extended, asshown. In this manner the conductors may be connected to correspondingconductors in another motor vehicle. Control of the circuits may beeffected by the operation of a single controller by making certainadditions to the above-described system.

As shown in Fig. 4, these circuit changes comprise the severance ofconductor 77 above the interlock 143. The upper portion of the conductoris then connected to provide a circuit through the actuating coil of therelay 150 andtheconductor 153 to the common conductor 148 leading toground at 131. c In order to effect the energization'of the actuatingcoil 121, a circuit is provided through the interlock 143, the relay 150and conductor 149 to the conductor 78, which is always energized whenthe controller has been advanced from its off position. It will beobserved that this does not affect the operation of the control system,since the coil 121 will be energized as before when the contact` finger77 engages contact segment 74a, inasmuch as the conductor 78 is alwaysyenergized when the controller is advanced from the ofi position, andcurrent will flow through coil 121 whenever the relay 150 is closed.

The conductor 79 is opened above the point where it is joined by theconductor 142 leadin from the cut-out switches 144 and 145. circuit isthen established from the conductor 79 through the actuating coil of therelay 152, conductor 154 and the commonline 148 to ground at 131. Thelower portion of the conductor 79 is connected through the relay 152 tothe conductor 78. Since the relay 152 is actuated only upon theenergization of conductor 179, the functioning of the coil 121 will bethe same as already described. e

Since various changes may be made in the above-described rconstructionand arrangement of parts, and different embodiments of the invention maybe made without departing from thescope thereof, it is intended that allmatter contained in the above description or shown in theaccompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

l claim as my invention:

l. ln a control system, the combination with a plurality ot'dynamo-electric machines, or' a plurality of cam switches operabie toset up predetermined circuits to provide Yfor series and parallelgrouping oit the maell unit switches disposed to close said circ-uns, acontroller co-operativc to ellect, through a single progressiveInovevaient, the actuation ot said switches, and means effect-dn'T aclosed-circuit transition of the machines from series to parallelrelation,

In a control system, the combination a plurality of dynamo-electric maora plurality et cam switches oper- 'edetermined circuits to proidparallel grouping of the I, switches disposed to close s; i circuits, acontroller' co-operative to e ect, through a. single progressive movetheactuation oi' the syvitones, and

for isolati 'i 3. In a control system, the combination with a pluralityof motors, of cam switches operable to set up dill'erent circuits togroup moors in series and parallel arrangements, a plurality ofresistance units disd to be cut into and out oit the motor s to controlthe acceleration or the .fm unit switches for closing the motor rits,and a controller co-operative to t, through single progressive movetheactuat on ct said switches, said suitciies bei adapted to establish a sce; and a parallel relation of the resistance units.

la a control system, the combination 'with a pluralityv of motors, ofcam switches operable to set up dii'erent motor circuits to group themotors in series and parallel arrangements`r a plurality of resistanceunits dispo ,d to be cut into and out of the motor circuits to controlthe acceleration of the motors, units switches for closing the motorcuits, a controller co-operative to etl'ect, through e si* rleprogressive movement, the d switches, and means for Y rmined number ofthe mot, is, sa. ,i isol g means being disposed to cooperate Witn thecontroller to control the establishment of circuit connections foroperating the remaii 'ng motors.

5. In a control system, the combination with a plurality of motors, otcam switches operable to set up different circuits to effect any desiredgrouping of the motors, unit switches for closing the motor circuits, acontroller co-operative to eil'ect the actuation of said switches, andmeans for isolating any predetermined number of the motors, saidisolating means being disposed to cooperate with the controller to eiectthe establishment of motor circuit connections for operating theremaining motors.

6. In a control system, the combination with a plurality of motors. ofcam switches operable to set up different circuits to group the motorsin series and parallel arrangements, unit switches for making andbreakin r said motor circuits, a controller co-operative to effect theactuation of the switches to establish series and parallel connectionsfor the motors, and means cio-operative to maintain a closed-circuittransition of the motors from series to parallel relation.

7. In a control system, the combination with a plurality of motors, ofcam switches operable to set up different circuits to group the motorsin series and parallel arrangements, unit switches for making andbreaking said motor circuits, a plurality of resistance units disposedto be cut into and out of the motor circuits to cont-rol theacceleration of the motors, means co-operative to establish a series anda parallel relation of the resistance units corresponding to the seriesand parallel connections of the motors, a controller adapted to effect,through a single progressive movement, the actuation of said switches,and means cooperative to maintain a closed-circuit transition of themotors from series to parallel relation.

8. In a control system, the combination with a plurality of motors, ofcam switches operable to set up different circuits to group the motorsin series and parallel arrangements, unit switches for making andbreaking said motor circuits, a plurality of resistance units disposedto be cut into and out of the motor circuits to control the accelerationof the motors, means co-operative to establish a series and a parallelrelation of the resistance units corresponding to the series andparallel connections of the motors, a controller adapted to effect,through a single progressive movement, the actuation of said switches,and means for isolating a predetermined number of the motors, saidisolating means being disposed to cooperate with the controller toestablish a combination of the series and parallelcircuit connections toprovide for connecting all the resistance units in series with theremaining motors.

9. In a control system, the combination with a plurality of motors, ofcam switches operable to set up different circuits to group the motorsin series and parallel arrangements, unit switches for making andbreaking said motor circuits, a plurality of resistance units disposedto be cut into and out of the motor circuits to control the accelerationof the motors, means co-operative to establish a series and a parallelrelation of the resistance units corresponding to the series andparallel connections of the motors, a controller adapted to eifect,through a single progressive movement, the actuation of said switches,and means for isolating a predetermined number of the motors, saidisolating means being disposed to cooperate with the controller toeffect the establishment of the parallel connections of the remainingmotors and the series relation of the resistance units.

l0. In a control system, the combination with a plurality of motors, ofcam switches operable to set up different circuits to group the motorsin series and parallel arrangements, unit switches for making andbreaking said motor circuits, a plurality of resistance units disposedto be cut into and out of the motor circuits to control the accelerationof the motors, means co-operative to establish a series and a parallelrelation of the resistance units corresponding to the series andparallel connections of the motors, a controller adapted to effect,through a single progressive movement, lthe actuation of said switches,means for isolating a predetermined number of the motors, said isolatingmeans being disposed to cooperate with the controller to control thecircuit connections established to operate the remaining motors, andmeans co-operative to maintain a closed-circuit transition from theseries connections of the motors to the parallel connections.

l1. In a control system, the combination with a plurality of motors, ofcam switches operable to set up different circuits to group the motorsin series and parallel relations, a plurality of resistance unitsdisposed to be cut into and out of the motor circuits to control theacceleration of the motors, unit switches disposed for making andbreaking the motor circuits, a controller cooperative to effect theoperation of the switches, and means co-operative to effect aclosed-circuit transition from the series to parallel relation of themotors and an opencircuit transition from parallel to series reulationmaybe effected through the operation of one controller.

In testimony whereof, I have hereunto subscribed my name this fourth dayof November, 1927.

JOHN A. CLARKE, Jn.

lation, said switches being adapted to establish series and parallelrelations of the resistance units.

*12. In a control system, the combination with a plurality of motors, ofcam switches operable to set up different circuits to group the motorsin series and parallel relations, a plurality of resistance unitsdisposed to control the acceleration of the motors, unit switches forclosing the motor circuits, a controller co-operative to effect, througha ysingle progressive movement, the actuation of said switches, andmeans connected into said control system to permit its connection to asimilar control system whereby manip-

